title: Regulation of growth by the trehalose pathway: relationship to temperature and sucrose.
abstract: Carbon signaling can override carbon supply in the regulation of growth. At least some of this regulation is imparted by the sugar signal trehalose 6-phosphate (T6P) through the protein kinase, SnRK1. This signaling pathway regulates biosynthetic processes involved in growth under optimal growing conditions. Recently, using a seedling system we showed that under sub-optimal conditions, such as cold, carbon signaling by T6P/ SnRK1 enables recovery of growth following relief of the stress. The T6P/ SnRK1 mechanism thus could be selected as a means of improving low temperature tolerance. High-throughput automated Fv/Fm measurements provide a potential means to screen for T6P/ SnRK1, and here we confirm through measurements of Fv/Fm in rosettes that T6P promotes low temperature tolerance and recovery during cold to warm transfer. Further, to better understand the coordination between sugars, trehalose pathway, and temperature-dependent growth, we examine the interrelationship between sugars, trehalose phosphate synthase (TPS), and trehalose phosphate phosphatase (TPP) gene expression and T6P content in seedlings. Sucrose, particularly when fed exogenously, correlated well with TPS1 and TPPB gene expression, suggesting that these enzymes are involved in maintaining carbon flux through the pathway in relation to sucrose supply. However, when sucrose accumulated to higher levels under low temperature and low N, TPS1 and TPPB expression were less directly related to sucrose; other factors may also contribute to regulation of TPS1 and TPPB expression under these conditions. TPPA expression was not related to sucrose content and all genes were not well correlated with endogenous glucose. Our work has implications for understanding acclimation to sink-limited growth conditions such as low temperature and for screening cold-tolerant genotypes with altered T6P/ SnRK1 signaling.
authors.affiliation: Plant Biology and Crop Science; Rothamsted Research; Harpenden, Hertfordshire UK.
authors.forename: Cátia
authors.initials: C
authors.lastname: Nunes
authors.affiliation: Molecular Plant Physiology; Utrecht University; Utrecht, The Netherlands.
authors.forename: Henriette
authors.initials: H
authors.lastname: Schluepmann
authors.affiliation: Molecular Plant Physiology; Utrecht University; Utrecht, The Netherlands.
authors.forename: Thierry L
authors.initials: TL
authors.lastname: Delatte
authors.affiliation: Genetics, Evolution, and Environment; University College London; London, UK.
authors.forename: Astrid
authors.initials: A
authors.lastname: Wingler
authors.affiliation: Instituto de Tecnologia Química e Biológica; Laboratório de Biotecnologia de Células Vegetais; Universidade Nova de Lisboa; Oeiras, Portugal; Departamento de Biologia Vegetal; Faculdade de Ciências da Universidade de Lisboa; Lisboa, Portugal.
authors.forename: Anabela B
authors.initials: AB
authors.lastname: Silva
authors.affiliation: Instituto de Tecnologia Química e Biológica; Laboratório de Biotecnologia de Células Vegetais; Universidade Nova de Lisboa; Oeiras, Portugal; Departamento de Biologia Vegetal; Faculdade de Ciências da Universidade de Lisboa; Lisboa, Portugal.
authors.forename: Pedro S
authors.initials: PS
authors.lastname: Fevereiro
authors.affiliation: Institute of Bio and Geosciences IBG-2; Plant Sciences; Forschungszentrum Jülich GmbH; Jülich, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Jansen
authors.affiliation: Institute of Bio and Geosciences IBG-2; Plant Sciences; Forschungszentrum Jülich GmbH; Jülich, Germany.
authors.forename: Fabio
authors.initials: F
authors.lastname: Fiorani
authors.affiliation: Institute of Bio and Geosciences IBG-2; Plant Sciences; Forschungszentrum Jülich GmbH; Jülich, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Wiese-Klinkenberg
authors.affiliation: Plant Biology and Crop Science; Rothamsted Research; Harpenden, Hertfordshire UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Paul
mesh_terms: D003080:Cold Temperature; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D053858:Metabolic Networks and Pathways / Q000187:drug effects* / Q000235:genetics; D063245:Plant Development / Q000187:drug effects* / Q000235:genetics; D013395:Sucrose / Q000494:pharmacology*; D013403:Sugar Phosphates; D014199:Trehalose / Q000031:analogs & derivatives / Q000378:metabolism*
chemical_list: D013403:Sugar Phosphates; C082722:trehalose-6-phosphate; D013395:Sucrose; D014199:Trehalose
keywords: Arabidopsis thaliana; Fv/Fm; SnRK1; cold; growth; high-throughput screening; sucrose; trehalose 6-phosphate